HD6412320 RENESAS [Renesas Technology Corp], HD6412320 Datasheet - Page 328

• Manufacturer Part Number: HD6412320
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family H8S-2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 7 DMA Controller (Not Supported in the H8S/2321)
Figure 7.34 shows an example of single address transfer using the write data buffer function. In
this example, the CPU program area is in on-chip memory.
When the write data buffer function is activated, the DMAC recognizes that the bus cycle
concerned has ended, and starts the next operation. Therefore, DREQ pin sampling is started one
state after the start of the DMA write cycle or single address transfer.
7.5.13
The DMAC channel priority order is: channel 0 > channel 1, and channel A > channel B. Table
7.13 summarizes the priority order for DMAC channels.
Table 7.13 DMAC Channel Priority Order
Short Address Mode
Channel 0A
Channel 0B
Channel 1A
Channel 1B
Rev.6.00 Sep. 27, 2007 Page 298 of 1268
REJ09B0220-0600
Figure 7.34 Example of Single Address Transfer Using Write Data Buffer Function
Internal read signal
External address
Internal address
DMAC Multi-Channel Operation
DACK
RD
φ
DMA
read
Full Address Mode
Channel 0
Channel 1
DMA
single
CPU
read
DMA
single
Priority
High
Low
CPU
read